JPH07114183A - Photopolymerizable composition and formation of cured coating film pattern using the same - Google Patents

Abstract

PURPOSE:To form the resist film free from danger such as a fire and toxicity and equal with thermosetting type, etc., by incorporating a specified ratio of photopolymerization initiator and a specified mica in a specified arom. epoxy resin deriv. CONSTITUTION:In 1kg resin, 0.1-10 pts.wt. photopolymerization initiator and 10-60 pts.wt. mica having 1-10mum average grain size are incorporated per 100 pts.wt. arom. epoxy resin deriv. having 0.3-10mol polymerizable unsatd. group and 0.1-3mol nonproton type onium salt-containing group expressed by formula I. In the formula I, R1 is hydroxyl, alkoxy, ester group or 1-8C hydrocarbon group which may be substituted with halogen atom or hydrogen atom. W is expressed by formula II. In the formula II, Z is nitrogen or phosphorus atom, Y is sulfur atom. R2-R4 each is 1-14C org. group. These R2 and R3 or R2-R4 together may form heterocyclic group with the nitrogen, phosphorus atom, etc., to which these are connected.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photopolymerizable composition, and more specifically, it can form a cured coating film having excellent adhesion to substrates, heat resistance and chemical resistance.
And since the uncured coating film can be removed simply by washing it off with water,
Particularly, it relates to a photopolymerizable composition suitable as a solder resist for producing a printed wiring board. Further, the present invention relates to a method for forming a cured coating film pattern using the above photopolymerizable composition.

[0002]

2. Description of the Related Art Conventionally, when a component is soldered to a printed wiring board or the like, the surface of the printed wiring board is protected for the purpose of avoiding adhesion of solder to portions other than a desired portion and also for protecting the circuit on the surface of the printed wiring board. Has a solder resist. In many cases, the solder resist is applied by printing the resist composition as a required pattern on a printed wiring board by a silk screen printing method or the like, followed by heat curing or curing with actinic rays such as ultraviolet rays. Has been done. In recent years, with the increase in the density of printed wiring, liquid type photo resists with high pattern formation accuracy have been proposed as solder resists. That is, a liquid photopolymerizable solder resist is applied on a printed wiring board by silk screen printing, roll coater coating, etc., and is dried by touch by heating, etc.
A film on which a necessary pattern is drawn is adhered to the coating film, and the exposed portion is cured by irradiating with actinic rays such as ultraviolet rays, and then the unexposed portion is dissolved and removed using a developing solution, and further heated if necessary. And post-curing by actinic ray irradiation to form a soldering pattern and a circuit protective film made of the solder resist as described above.

[0003]

By the way, most of the conventional solder resists as described above use an organic solvent as a developing solution, and some of them use an alkaline aqueous solution instead of the organic solvent. ing. However, the use of an organic solvent as a developer has safety and health problems such as a risk of fire and toxicity to humans. On the other hand, a solder resist using an alkaline aqueous solution as a developing solution has a problem that the resist film using the same is inferior in performance to a thermosetting type or an organic solvent developing type.

Therefore, the present invention has been proposed in view of the conventional circumstances, and there is no problem of safety and hygiene such as danger of fire and toxicity to the human body, and the conventional thermosetting type or organic solvent development type is adopted. An object of the present invention is to provide a photopolymerizable composition suitable as a solder resist capable of forming a resist film having the same properties as a solder resist, and to provide a method for forming a cured coating film pattern using the same.

[0005]

As a result of intensive studies by the present inventors in order to achieve the above-mentioned object, JP-A-2-
By adding a specific amount of mica having a specific particle size to the specific photopolymerizable composition disclosed in Japanese Patent No. 1858, it is possible to use a completely harmless water or dilute acid aqueous solution having a higher safety than an alkaline aqueous solution as a developer. It has also been found that it is possible to form a resist film having properties not inferior to the conventional thermosetting type or organic solvent developing type solder resist, and to obtain a photopolymerizable composition suitable as a solder resist.

That is, the photopolymerizable composition of the present invention is represented by the following chemical formula 2 in which 0.3 mol or more and 10 mol or less of polymerizable unsaturated groups and 0.1 mol or more and 3 mol or less are contained in 1 kg of resin. With respect to 100 parts by weight of the aromatic epoxy resin derivative having an aprotic onium salt-containing group, the photopolymerization initiator is 0.1 parts by weight or more and 10 parts by weight or less, and the average particle size is 1 μm.
It is characterized by containing mica of m or more and 10 μm or less in an amount of 10 parts by weight or more and 60 parts by weight or less.

[0007]

[Chemical 2]

Further, the method for forming a cured coating film pattern of the present invention comprises a step of forming a coating film of the above-mentioned photopolymerizable composition on a substrate, a step of drying the formed coating film, and It is characterized by having a step of exposing through a photomask having a circuit pattern, a step of washing the coating film with water to remove an unexposed portion, and a step of heat-treating the coating film having a circuit pattern. is there.

The aromatic epoxy resin derivative in the photopolymerizable composition of the present invention is required to have a polymerizable unsaturated group and an aprotic onium salt-containing group represented by the chemical formula 2 in the resin. Then, in order to obtain the above aromatic epoxy resin derivative, a polymerizable unsaturated group and an aprotic onium salt-containing group may be introduced into the aromatic epoxy resin.

At this time, the polymerizable unsaturated group may be introduced into the epoxy resin which becomes the cation of the onium salt, or acrylic acid as the organic acid which becomes the anion of the onium salt,
It may be introduced into the anion by using a carboxylic acid having a polymerizable unsaturated group such as methacrylic acid, crotonic acid, maleic acid monomethyl ester, fumaric acid monomethyl ester and itaconic acid monomethyl ester.

Typical examples of the aromatic epoxy resin include diglycidyl ether compounds of aromatic bisphenols such as bisphenol A, bisphenol F and bisphenol S, polymers of these diglycidyl ether compounds and the above bisphenol, and phenol novolac type resins. Examples thereof include epoxy resins, cresol novolac type epoxy resins, triglycidyl isocyanurate, and their nuclear halides. Further, those obtained by partially modifying these epoxy resins with benzoic acid or the like can also be used. In the above aromatic epoxy resin, the epoxy group content in the resin is 0.
It is preferably 1 mol or more, and the molecular weight of the resin is not particularly limited, but the weight average molecular weight is about 500 or more from the viewpoint of dryness to the touch when forming a cured coating film of a resist or the like, and a coating operation. From the viewpoint of sex, the weight average molecular weight is about 500.
It is preferably 0 or less.

Examples of the polymerizable unsaturated group include acryloyl group, methacryloyl group, itaconate group, maleate group, fumarate group, crotonate group, acrylamide group, methacrylamide group, cinnamic acid group, vinyl group and allyl group. To be

The aprotic onium salt-containing group is represented by the above chemical formula 2 and is a hydroxyl group having a secondary carbon atom at the β-position from the nitrogen atom, phosphorus atom or sulfur atom of the onium salt. It is necessary that the group has.
Such an aprotic onium salt is any one of a quaternary ammonium salt, a quaternary phosphonium salt and a tertiary sulfonium salt. Specific examples of the cation in the aprotic onium salt-containing group are shown in Chemical formula 3, Chemical formula 4, and Chemical formula 5.

[0014]

[Chemical 3]

[0015]

[Chemical 4]

[0016]

[Chemical 5]

At this time, in the above Chemical Formula 3, Chemical Formula 4, and Chemical Formula 5, as the organic group having 1 to 14 carbon atoms represented by R ₂ , R ₃ and R ₄ , ionization of ammonium base, phosphonium base or sulfonium base is performed. It is not particularly limited as long as it does not substantially interfere, and for example, a hydrocarbon group having 1 to 14 carbon atoms which may contain a hetero atom such as an oxygen atom in the form of a hydroxyl group, an alkoxy group or the like is generally used. To be

As such a hydrocarbon group, an alkyl group,
Examples thereof include aliphatic, alicyclic or aromatic hydrocarbon groups such as a cycloalkyl group, a cycloalkylalkyl group, an aryl group and an aralkyl group. The alkyl group may be linear or branched, and has 8 or less carbon atoms,
It is preferably a lower one, for example, methyl, ethyl, n- or iso-propyl, n-, iso-,
Examples thereof include sec- or tert-butyl, pentyl, heptyl and octyl groups. The cycloalkyl group or cycloalkylalkyl group has 5 to 5 carbon atoms.
Eight is preferable, and examples thereof include a cyclopentyl, cyclohexyl, cyclohexylmethyl, cyclohexylethyl group and the like. The aryl group includes phenyl,
Toluyl, xylyl group and the like are included. A benzyl group is suitable as the aralkyl group.

Preferred examples of the hydrocarbon group containing a hetero atom such as an oxygen atom are hydroxyalkyl groups (especially hydroxy lower alkyl groups), specifically hydroxymethyl, hydroxyethyl, hydroxybutyl, hydroxypentyl. , A hydroxyheptyl, a hydroxyoctyl group and the like, an alkoxyalkyl group (particularly a lower alkoxy lower alkyl group), specifically methoxymethyl, ethoxymethyl, ethoxyethyl, n-propoxyethyl, iso-propoxymethyl, n-butoxymethyl, Examples thereof include an iso-butoxyethyl group and a tert-butoxyethyl group.

[0020] if R ₂ and R ₃ or R _2, R ₃ and R ₄ together the nitrogen atom to which they are attached, a heterocyclic group to form together with the phosphorus atom or sulfur atom -W ⁺ Examples of the compounds include those shown in Chemical formulas 6 to 14.

[0021]

[Chemical 6]

[0022]

[Chemical 7]

[0023]

[Chemical 8]

[0024]

[Chemical 9]

[0025]

[Chemical 10]

[0026]

[Chemical 11]

[0027]

[Chemical 12]

[0028]

[Chemical 13]

[0029]

[Chemical 14]

Further, the hydroxyl group, alkoxy group, ester group or hydrocarbon group having 1 to 8 carbon atoms which may be substituted by a halogen atom represented by R ₁ in the above chemical formula 2 is an alkyl group, an alkenyl group or a cycloalkyl group. Examples thereof include aliphatic, alicyclic or aromatic hydrocarbon groups such as an alkyl group, a cycloalkylalkyl group, an aryl group and an aralkyl group. Of these, an alkyl group and an alkenyl group are preferable, and these groups may be linear or branched, and particularly lower one is preferable, for example, methyl,
Ethyl, n- or iso-propyl, n-, iso
Examples thereof include-, sec- or tert-butyl, pentyl, heptyl, octyl, vinyl and 2-methylvinyl groups. Preferred examples of the hydroxyl group-substituted hydrocarbon group include a hydroxyalkyl group (particularly a hydroxy lower alkyl group), specifically, a hydroxymethyl, hydroxyethyl, hydroxybutyl, hydroxypentyl, hydroxyheptyl, hydroxyoctyl group and the like. Preferred examples of the alkoxy group-substituted hydrocarbon group are alkoxyalkyl groups (particularly lower alkoxy lower alkyl groups), specifically methoxymethyl, ethoxymethyl, ethoxyethyl, n-propoxyethyl, iso-propoxymethyl, n-butoxy. Examples thereof include methyl, iso-butoxyethyl and tert-butoxyethyl groups. Preferred examples of the ester group-substituted hydrocarbon group include a lower alkoxycarbonylalkyl group, a lower alkoxycarbonylalkenyl group and the like, specifically, methoxycarbonylmethyl, propoxycarbonylethyl, ethoxycarbonylpropyl, methoxycarbonylbutyl, methoxycarbonylethylenyl, Examples thereof include an ethoxycarbonylethylenyl group. Preferable examples of the halogen atom-substituted hydrocarbon group include chloromethyl, bromomethyl,
Examples thereof include iodomethyl, dichloromethyl, trichloromethyl, chloroethyl and chlorobutyl groups.

At this time, the polymerizable unsaturated group in the aromatic epoxy resin derivative has a resin solid content of 1 from the viewpoint of curability.
It is preferably in the range of 0.3 to 10 mol per kg, and more preferably in the range of 0.5 to 5 mol.
If it is less than 0.3 mol, curing of the resin will be insufficient, while if it is more than 10 mol, the mechanical properties of the cured product will tend to be deteriorated.

The aprotic onium salt-containing group is preferably in the range of 0.1 to 3 mol, and more preferably 0.3 to 2 mol, per 1 kg of the resin solid content. If it is less than 0.1 mol, curing tends to be insufficient, which is not preferable. On the other hand, if the amount is more than 3 mol, the water resistance of the cured product obtained by curing may decrease, which is not preferable.

Incidentally, the introduction of the polymerizable unsaturated group into the aromatic epoxy resin can be carried out by adopting a conventionally known means. For example, (1) an addition reaction between a carboxyl group and an epoxy group, (2) an addition reaction between a hydroxyl group and an epoxy group can be used, and when a hydroxyl group is present in an epoxy resin, (3) between an carboxyl group and a hydroxyl group. Epoxy resin utilizing esterification reaction, (4) addition reaction between isocyanate group and hydroxyl group, (5) half esterification reaction between acid anhydride and hydroxyl group, (6) transesterification reaction between ester group and hydroxyl group, etc. It can be carried out by using a compound having a functional group capable of reacting with a functional group therein and a polymerizable unsaturated group.

Among the above reactions, as a typical example (1),
(2) and (4) will be described below. Above (1)
Examples of the compound having a polymerizable unsaturated group and a carboxyl group that can be used in the reaction include (meth) acrylic acid, crotonic acid, itaconic acid monoalkyl ester, maleic acid monoalkyl ester, fumaric acid monoalkyl ester, and the like. . Further, as the compound having a polymerizable unsaturated group and a hydroxyl group that can be used in the above reaction (2), 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, allyl alcohol, N-
Examples thereof include monoalcohols having a polymerizable unsaturated group such as methylol (meth) acrylamide. Also above (4)
Examples of the compound having a polymerizable unsaturated group and an isocyanate group that can be used for the reaction include a monoalcohol having a polymerizable unsaturated group and tolylene diisocyanate, an equimolar adduct of a diisocyanate compound such as isophorone diisocyanate and α, A method of adding α-dimethyl-m-isopropenylbenzyl isocyanate or the like can also be used.

The introduction of the onium salt into the aromatic epoxy resin is carried out, for example, in a solvent-free or inert organic solvent by adding a tertiary amine, phosphine or thioether and a resin having a 1,2-epoxy group. It can be carried out by a method of simultaneously reacting an organic acid.

Taking a case where a tertiary amine is used as a compound to be reacted with the above resin, the reaction formula is as shown in Chemical formula 15.

[0037]

[Chemical 15]

When phosphine is used instead of the tertiary amine, N may be replaced with P in the above reaction formula, and when thioether is used instead of the tertiary amine, N is replaced in the above reaction formula. It may be replaced with S and -R ₄ may be deleted. The reaction of the resin, the tertiary amine, etc. and the organic acid is carried out under heating at about 40 to 80 ° C, and the reaction is completed in about 1 to 20 hours.

Further, the introduction of the onium salt into the aromatic epoxy resin can be carried out by using a solventless or inert organic solvent.
It is also carried out by a method of reacting a resin having a -halogeno-1-hydroxyethyl group with a tertiary amine, phosphine or thioether, then substituting a halogen atom for a hydroxyl group by anion exchange, and then reacting this with an organic acid. be able to.

Examples of the inert organic solvent used when introducing the onium salt into the aromatic epoxy resin as described above include ether alcohol solvents such as ethylene glycol monobutyl ether and ethylene glycol monoethyl ether, dioxane and ethylene. Examples thereof include ether solvents such as glycol diertyl ether, alcohol solvents such as ethanol, propanol and butanol, and ketone solvents such as methyl ethyl ketone and methyl isobutyl ketone.

The organic acid (HOCOR ₁ ) is R
_{As long as 1} is an organic carboxylic acid that generates an anion showing a hydroxyl group, an alkoxy group, an ester group or a hydrocarbon group having 1 to 8 carbon atoms which may be substituted by a halogen atom, conventionally known ones can be widely used. , Specifically, acetic acid, formic acid,
Examples are trimethylacetic acid, acrylic acid, methacrylic acid, lactic acid, hydroxyacetic acid, crotonic acid, chloroacetic acid, maleic acid monomethyl ester, fumaric acid monoethyl ester, and itaconic acid monomethyl ester. Among these, those having a dissociation constant (pKa value) of 1 × 10 ⁻⁵ or more are particularly preferable.

As the photopolymerization initiator in the photopolymerizable composition of the present invention, known photopolymerization initiators are generally used. Examples thereof include benzoin, benzoin methyl ether, benzoin ethyl ether, benzyl, diphenyl disulfide, tetramethylthiuram monosulfide, eosin, Thionine,
Diacetyl, Michler's ketone, anthraquinone, chloranthraquinone, methylanthraquinone, α-hydroxyisobutylphenone, P-isopropyl α-hydroxyisobutylphenone, α, α′-dichloro-4-phenoxyacetophenone, 1-hydroxy1-cyclohexylacetophenone, 2,2 -Dimethoxy 2-phenylacetophenone, methyl benzoyl formate, 2-
Methyl-1- [4- (methylthio) phenyl] -2-morpholino-propene, thioxanthone, benzophenone and the like can be applied, and the amount of these is 0.1 to 10 parts by weight with respect to 100 parts by weight of the resin component (solid content). When the amount is less than 0.1 parts by weight, the curability tends to decrease, and when it exceeds 10 parts by weight, the mechanical strength of the cured product tends to deteriorate.

By the way, the specific photopolymerizable composition disclosed in the above-mentioned JP-A No. 2-1858 is composed of the aromatic epoxy resin derivative as described above and a photopolymerization initiator, and is completely harmless in water. Alternatively, a dilute aqueous acid solution can be used as a developer, but when the photopolymerizable composition is applied onto a printed wiring board to form a cured coating film, a dried film thickness of 5 to 5 is often formed on the circuit portion. There was a problem that a 15 μm thin film portion was partially generated, and after the soldering treatment under severe conditions, the adhesion of the cured coating film became unstable at the corner portion of the circuit portion where the thin film portion was generated.

The generation of the thin film portion can be avoided by carefully controlling the coating conditions such as the coating thickness, but it is not preferable because there is a problem that the coating work efficiency decreases.

Then, as a result of earnest research by the present inventors,
Mica having an average particle size of 1 to 10 μm was prepared as described in JP-A-2-185.
It has been found that the above-mentioned disadvantages can be solved by containing 10 to 60 parts by weight with respect to 100 parts by weight of the aromatic epoxy resin derivative in the photopolymerizable composition disclosed in JP-A-8. That is, as a result of the study by the present inventors, by adding a scale-like additive to the photopolymerizable composition, particularly mica, the adhesion of the cured coating film of the photopolymerizable composition to a printed wiring board is improved. Was found to be greatly improved.

During the study, the present inventors also examined inorganic fillers having a substantially spherical shape, such as barium sulfate and silica, and even if these are added to the photopolymerizable composition, the cured coating film The adhesion to the printed wiring board was not improved. On the other hand, it was confirmed that when a filler such as mica and talc having a scale-like shape was added to the photopolymerizable composition, the adhesion of the cured coating film to the printed wiring board was significantly improved.

As shown in FIG. 1, when the photopolymerizable composition 1 to which the scale-like filler 2 is added is applied on the printed wiring board 4 on which the circuit 3 is formed to form a cured coating film, It is considered that the filler 2 in the photopolymerizable composition 1 is oriented in a direction parallel to the printed wiring board because the filler 2 has a scaly shape. As a result of further studies by the present inventors, talc is inferior to mica in adhesion improving effect, and when it is used, it is necessary to increase the compounding amount, so that the resulting photopolymerizable composition is coated. It was confirmed that it is not preferable to use talc, and it is preferable to use mica, because disadvantages such as a remarkable decrease in film surface hardness and a decrease in appearance of the coating film surface occur.

Then, the remarkable improvement effect seen in the present invention is realized only by incorporating a specific amount of the above-mentioned mica having a specific particle size. That is, the average particle size of mica is 1μ.
When it is less than m, the effect of improving the adhesion is poor, and when it is more than 10 μm, it is difficult to obtain a smooth coating film and the appearance quality is poor, and the resolution when a cured coating film pattern is formed is deteriorated. Absent. The content is 10
If it is less than part by weight, the effect of improving the adhesion is not sufficient, and 60
If the amount is more than parts by weight, the viscosity of the coating liquid of the photopolymerizable composition remarkably increases, the dispersibility of mica in the photopolymerizable composition decreases, and problems such as difficulty in coating occur, which are not preferable. .

The photopolymerizable composition of the present invention may be composed of only the aromatic epoxy resin derivative, the photopolymerization initiator and mica, but is it usually used as an organic solvent type in view of coatability and the like? Or, use a water-miscible solvent as a solvent at the time of resin preparation, and add water to the resulting resin liquid,
Alternatively, by blending in water, it is used in the state of an aqueous solution or an aqueous dispersion.

The solvent is not particularly limited as long as it can dissolve or disperse the aromatic epoxy resin derivative, the photopolymerization initiator and the mica in the present invention. For example, acetic acid esters such as ethyl acetate and butyl acetate. Glycol ethers such as ethylene glycol, diethylene glycol and propylene glycol; aromatic hydrocarbons such as toluene and xylene; alcohols such as methanol, ethanol and butanol; ketones such as methyl ethyl ketone and methyl isobutyl ketone; water and the like. . These solvents can be used alone or as a mixture, and the amount used is appropriately adjusted depending on the coating method of the composition and the like.

In the photopolymerizable composition of the present invention, if necessary, alkali metal hydroxides such as sodium hydroxide and lithium hydroxide; alkaline earth metal hydroxides such as calcium hydroxide and magnesium hydroxide. A curing catalyst for thermosetting such as hydroxide, organic acid salt and alkoxide of a metal selected from nickel, copper, molybdenum, lead, iron, chromium, manganese, tin and cobalt may be added. The amount of these curing touch media added is 100 per 100 parts of the aromatic epoxy resin derivative.
It is preferably 10 parts by weight or less, more preferably 0.1 to 5 parts by weight with respect to parts by weight.

Further, the photopolymerizable composition of the present invention further includes a coloring pigment, an extender pigment, a rust preventive pigment, a dye, a thermoplastic polymer, a polyfunctional vinyl monomer or oligomer, other leveling agent, and defoaming agent. Various additives such as anti-sagging agents may be blended. As the coloring pigment, extender pigment, rust preventive pigment and dye, those generally used in the field of inks and paints can be used, and 50% by weight or less, and further 30% by weight or less in the solid content of the photopolymerizable composition of the present invention. It is preferable to blend in the range of. Examples of the polyfunctional vinyl monomer or oligomer include trimethylolpropane tri (meth)
Acrylate, dipentaerythritol (meth) acrylate, norbornene di (meth) acrylate, tricyclodecane dimethanol di (meth) acrylate, etc. are mentioned, and these polyfunctional vinyl monomers or oligomers and thermoplastic polymers are blended. The amount is preferably 30% by weight or less based on the solid content of the photopolymerizable composition of the present invention.

To form a cured coating film pattern using the photopolymerizable composition of the present invention, the photopolymerizable composition of the present invention is formed on a substrate and the formed coating film is dried. After that, the coating film is exposed through a photomask having a desired circuit pattern, the coating film is washed with water to remove an unexposed portion, and then the coating film having the circuit pattern is heat-treated.

The coating film is formed on the substrate by a conventional method such as spray coating, brush coating, roll coating, dip coating, silk screen printing, etc., and the film thickness is usually 10 to 100 μm as a dry film thickness. It is said that Further, the formed coating film may be dried by touching at a temperature of 100 ° C. or lower, for example. The exposure of the coating film is performed by irradiating with actinic rays such as ultraviolet rays at 10 mj / cm ^{2 to} 2000 mj / cm ² , preferably 100 mj / cm ^{2 to} 1000 mj / cm ² . As the exposure device at this time, those conventionally used for curing actinic rays such as ultraviolet rays can be used, and examples thereof include an ultrahigh pressure mercury lamp and a high pressure mercury lamp. Further, the water used for removing the unexposed portion is not particularly limited, and examples thereof include deionized water, distilled water, city water, and industrial water. And the heat treatment of the coating film is 120
It may be carried out at about 180 ° C. for about 10 to 60 minutes.

[0055]

The photopolymerizable composition of the present invention comprises 0.3 mol or more and 10 mol or less of a polymerizable unsaturated group and 0.1 mol or more and 3 mol or less of the aproton represented by the following chemical formula 16 in 1 kg of resin. 0.1 parts by weight or more and 10 parts by weight or less of a photopolymerization initiator and an average particle size of 1 μm or more, 1
Since it contains mica of 0 μm or less in an amount of 10 parts by weight or more and 60 parts by weight or less, the developer is water or a dilute aqueous acid solution,
Adhesion of the cured coating film using this to the substrate is improved.

[0056]

[Chemical 16]

[0057]

EXAMPLES Specific examples to which the present invention is applied will be described below. That is, a photopolymerizable composition to which the present invention was applied was prepared, a cured coating film pattern was formed using the composition, and its characteristics were investigated. In addition, hereinafter, what is simply described as “part” and “%” means “part by weight”,
It means "% by weight".

Production of Aromatic Epoxy Resin Derivative Solution First, two types of aromatic epoxy resin derivative solutions for producing a photopolymerizable composition were produced. [Resin derivative solution A-1 raw material composition] Epicoat 154 500 parts (Plastic novolac type epoxy resin manufactured by Yuka Shell Epoxy Co., number average molecular weight about 500, epoxy equivalent about 174) Acrylic acid 180 parts Tetraethylammonium bromide 1.0 part Hydroquinone 0.5 part After blending and dissolving the raw material having the above composition in a flask containing 250 parts of ethylene glycol monobutyl ether,
It heated at 110 degreeC for 5 hours, and obtained the epoxy ester solution of resin acid value 0.5. After cooling the solution to about 50 ° C,
36 parts of N, N-dimethylethanolamine and 24 parts of acetic acid were added and reacted at 70 ° C. for 6 hours to obtain a resin derivative solution A-1 having a solid content of 75%. The solid content of this resin derivative was 3.4 mol / kg of polymerizable unsaturated groups and 0.55 mol / kg of quaternary ammonium salt.

[Resin Derivative Solution A-2 Raw Material Composition] Epicoat 190S80 500 parts (cresol novolac type epoxy resin manufactured by Yuka Shell Epoxy Co., number average molecular weight about 1100, epoxy equivalent about 210) Acrylic acid 171 parts Thiodiglycol 122 Parts Methoxyhydroquinone 0.5 parts The raw material having the above composition was blended and dissolved in a flask containing 350 parts of diethylene glycol monoethyl ether, and the mixture was heated at 70 ° C. for 10 hours to prepare a resin derivative solution A-2 having a solid content of 69%. Got This resin derivative had a polymerizable unsaturated group of 3.0 mol / kg and a tertiary sulfonium salt of 1.26 mol / kg in solid content.

Preparation of Photopolymerizable Compositions Examples 1 to 3 and Comparative Examples 1 to 4 of the photopolymerizable compositions using the above resin derivative solutions A-1 and A-2 are shown in Table 1. Produced with a compounding.

[0061]

[Table 1]

In Table 1, the photopolymerization initiator A represents α-hydroxyisobutylphenone and B represents benzoin monoethyl ether. Mica C has an average particle size of 7.6 μm, Mica D has an average particle size of 5.3 μm, Mica E has an average particle size of 2.4 μm, and Mica F has an average particle size of 2.4 μm.
Indicates an average particle size of 0.5 μm (mica E pulverized and classified by a jet mill). In addition, Modaflow indicates a surface conditioner manufactured by Monsanto, USA.

That is, for example, as shown in Table 1, the photopolymerizable composition of Example 1 has a resin derivative solution A-1.
135 parts of α-hydroxyisobutylphenone
Part, 0.5 parts of phthalocyanine green, 15 parts of mica C
Parts, 30 parts of barium sulfate and 1.5 parts of modaflow are dispersed in water and kneaded by a test roll.

In addition, Examples 2-3 and Comparative Examples 1-4 are manufactured in the same manner. However, only Example 2 and Comparative Example 2 were not dispersed in water at the time of kneading with a test roll, but were diluted with water after kneading.

Formation of Cured Coating Pattern Next, the above photopolymerizable compositions of Examples 1 to 3 and Comparative Examples 1 to 1 were formed .
4 was used to form a cured coating film pattern on a printed wiring board. For example, the photopolymerizable composition of Example 1 is applied (printed) on a pre-etched copper through-hole printed wiring board by a silk screen method so as to have a dry film thickness of 7 to 10 μm (circuit plane portion). A coating film is formed and the coating film is
After being dried at 10 ° C. for 10 minutes, 400 mj / cm ² and 800 mj of a polyethylene terephthalate film is applied to the coating film through a photomask having a predetermined circuit pattern.
/ Cm ² of light, and the unexposed areas are washed with water to remove and develop, then the coating film with the circuit pattern is heated to 150 ° C.
And heat-treated for 30 minutes to form a cured coating film pattern. The printed wiring board on which this cured coating film pattern is formed is referred to as Example 1 for convenience. Then, Example 3 and Comparative Example 1,
Similarly, for 3 and 4, a cured coating film pattern is formed on the printed wiring board, and these are referred to as Example 3 and Comparative Examples 1, 3, and 4 for convenience. However, in Example 2 and Comparative Example 2, a dry film thickness of 7 to 10 was applied to the circuit portion on the same printed wiring board as in Example 1 by a high-speed rotating disk type electrostatic coating machine.
A coating film is formed by coating (spraying) so as to have a thickness of .mu.m, and thereafter, the manufacture is carried out in exactly the same manner as in Example 1, and for convenience sake, Example 2 and Comparative Example 2 are obtained.

Then, the above Examples 1 to 3 and Comparative Examples 1 to 1
4 was investigated by the method shown below, and the results are shown in Table 2.
It was shown to.

[0067]

[Table 2]

The image forming properties in Table 2 are as follows: water on the coating film after exposure at 25 ° C. and a spraying pressure of 2 kg / c during the forming process.
The degree of development of the through hole when sprayed at m ² for a predetermined time (90 seconds and 180 seconds) was investigated. In Table 2, ⊚ indicates a state in which the development is completed up to the inside of the through hole, ◯ indicates a state in which the coating film surface is completely developed, and Δ indicates a portion where the coating film surface cannot be developed or The state where image defects are caused by erosion, swelling, etc. by a developing solution is shown, and x indicates a state where almost no development is performed.

In Table 2, the initial adhesiveness is 100 μm formed on the printed wiring board in each Example and Comparative Example.
Adhesive tape (Nichiban C
T-24) was pressure-bonded and rapidly peeled off, and the peeled state was observed by a 40 × microscope and investigated. Table 2
Medium ◎ indicates a state without peeling, and × indicates a state with peeling.

In Table 2, the adhesion after soldering treatment was measured according to JIS C-6481 after applying rosin-based solder flux to each Example and Comparative Example.
Floating in a solder bath at 260 ° C. for 10 seconds and leaving them until they cool down to room temperature is one cycle. After three cycles, peeling of the corner portion of the cured coating pattern is performed in the same manner as the above initial adhesion. It is a survey of the condition. In addition, after this, further 5 cycles were performed, and the peeled state was similarly examined even after performing a test of a total of 8 cycles. In Table 2, ⊚ indicates a state without peeling, ○ indicates a state of slight peeling (the length of the peeled corner is within 5% of the length of the corner to be evaluated), and Δ indicates the corner to be evaluated. The length of the peeled corner is 30 against the length
%, And x represents a state in which the length of the peeled corner is 50% or more with respect to the length of the corner portion to be evaluated.

Further, in Table 2, the storage stability was determined by placing the photopolymerizable compositions of Examples and Comparative Examples in 100 cc glass bottles, sealing them, and leaving them in the dark at 30 ° C. for a remarkable increase in viscosity or gelation. The resulting time was measured and investigated.

As can be seen from the results in Table 2, the average particle size of the mica contained in the photopolymerizable composition is in the range of 1 to 10 μm, and the content is in the range of 10 to 60 parts. In Examples 1 to 3, good results were obtained for all characteristics. On the other hand, in Comparative Examples 1 and 3 containing no mica, the result of the adhesion after the soldering treatment was poor, and the adhesion of the cured coating film of the photopolymerizable composition to the printed wiring board was not improved. all right. Further, in Comparative Example 2 in which the particle size of the contained mica was extremely small and out of the above range, the adhesion after the soldering treatment was improved, but a sufficient result was not obtained. (It should be noted that it has already been confirmed that it is difficult to form a smooth coating film when the particle size of the mica contained is larger than the above range. .)further,
Also in Comparative Example 4 in which the content of mica was less than the above range, the adhesion result after soldering treatment was poor, and the adhesion of the cured coating film of the photopolymerizable composition to the printed wiring board was not improved. I understood it. (Note that it has been confirmed that when the content of mica is more than the above range, the viscosity of the coating liquid of the photopolymerizable composition remarkably increases.

Therefore, as in the photopolymerizable composition of this example, 1 kg of resin contains 0.3 to 10 mol of a polymerizable unsaturated group and 0.1 to 3 mol of a specific aprotic onium salt. 0.1 to 10 parts of a photopolymerization initiator and an average particle size of 1 to 100 parts of the aromatic epoxy resin derivative having a group.
In the photopolymerizable composition containing 10 to 60 parts of 10 μm mica, the adhesion of the cured coating film to the printed wiring board is good, which is shown in the image forming property, the initial adhesion property and the adhesion property after the soldering treatment. Because of this, it is possible to form a resist film having characteristics equivalent to those of the conventional thermosetting or organic solvent development type solder resist. Further, since water and a dilute aqueous acid solution can be used as a developing solution and the storage stability is very good, there are no safety and hygiene problems such as a risk of fire and toxicity to the human body.

[0074]

As is apparent from the above description, the photopolymerizable composition of the present invention contains 0.3 mol or more and 10 mol or less of a polymerizable unsaturated group and 0.1 mol or more per 1 kg of resin. 0.1 parts by weight or more of a photopolymerization initiator with respect to 100 parts by weight of the aromatic epoxy resin derivative having an aprotic onium salt-containing group represented by the following chemical formula 17 of 3 mol or less.
Since it contains 10 parts by weight or more and 60 parts by weight or less of mica having a weight part or less and an average particle size of 1 μm or more and 10 μm or less, the developer is water or a dilute aqueous acid solution, and there is a risk of fire or the like to the human body. There are no health and safety issues such as toxicity,
Since the adhesion of the cured coating film using this to the substrate is improved, it is possible to form a cured coating film having the same characteristics as the conventional thermosetting or organic solvent developing type solder resist.

[0075]

[Chemical 17]

Further, the method for forming a cured coating film pattern of the present invention comprises a step of forming a coating film of the above-mentioned photopolymerizable composition on a substrate, a step of drying the formed coating film, and a desired coating film of the above-mentioned coating film. There is a risk of fire etc. because it has a step of exposing through a photomask having a circuit pattern, a step of washing the coating film with water to remove the unexposed portion, and a step of heat-treating the coating film having a circuit pattern. , A cured coating pattern can be formed without causing safety and health problems such as toxicity to the human body, adhesion of the cured coating to the substrate is improved, and conventional thermosetting or organic solvent development type solder It is possible to form a cured coating film pattern having the same characteristics as the resist film of the resist.

[Brief description of drawings]

FIG. 1 is an enlarged sectional view of an essential part schematically showing a state in which a photopolymerizable composition is applied to a printed wiring board.

[Explanation of symbols]

 1 ... Photopolymerizable composition 2 ... Filler 3 ... Circuit 4 ... Printed wiring board

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inami Mami Konishi 6-735 Kitashinagawa, Shinagawa-ku, Tokyo Sony Corporation (72) Inventor Naozumi Iwasawa 4-17-1, Higashi-Hachiman, Hiratsuka-shi, Kanagawa Seki Nishi Paint Co., Ltd. (72) Inventor Satoshi Furusawa 4-17-1, Higashihachiman, Hiratsuka City, Kanagawa Kansai Paint Co., Ltd.

Claims (2)

[Claims] 1. A fragrance having 0.3 mol or more and 10 mol or less of a polymerizable unsaturated group and 0.1 mol or more and 3 mol or less of an aprotic onium salt-containing group represented by the following chemical formula 1 in 1 kg of a resin. To 100 parts by weight of the group epoxy resin derivative,
Photopolymerizability, characterized by containing 0.1 part by weight or more and 10 parts by weight or less of a photopolymerization initiator and 10 parts by weight or more and 60 parts by weight or less of mica having an average particle size of 1 μm or more and 10 μm or less. Composition. [Chemical 1] 2. A step of forming a coating film of the photopolymerizable composition according to claim 1 on a substrate, a step of drying the formed coating film, and a photomask having a desired circuit pattern on the coating film. A method for forming a cured coating film pattern, which comprises a step of exposing, a step of washing the coating film with water to remove an unexposed portion, and a step of heat-treating the coating film having a circuit pattern.